The impact of stormwater management strategies on the flow regime of a peri-urban catchment facing urbanisation and climate change: a distributed modelling study in Lyon, France

The relative impact of urbanisation (urban sprawl), climate change (rainfall and evapotranspiration) and stormwater disconnection strategies (implementation of green infrastructure (GI)) on a peri-urban stream in the western suburbs of Lyon, France, was investigated using a distributed, physically based model (J2000P). Results showed that ambitious catchment-scale implementation of GI has the potential to mitigate some hydrological effects of urbanisation, especially a drastic reduction of combined sewer overflows. However, GI did not have a large impact on the stream flow regime, especially in the context of climate change, as the stream is dominated by non-urban contributions. Spatially distributed models have the capacity to inform river managers about the extent of implementation of GI needed to achieve given management goals and highlight some limitations of disconnection strategies. Indeed, while GI improved the resilience of sewer networks to global change, it was not sufficient to compensate for the effects of climate change on streamflow.

本研究以法国里昂西郊的一条城郊溪流为研究对象，采用分布式物理机理模型J2000P，探究了城市化（城市蔓延）、气候变化（降雨与蒸散发）以及雨水截留策略（绿色基础设施（GI）实施）对其产生的相对影响。研究结果显示，在流域尺度高标准推行绿色基础设施（GI）建设，有望缓解城市化带来的部分水文效应，尤其可大幅减少合流制溢流事件。但由于该溪流的径流主要源自非城市区域，绿色基础设施对河流水文情势的影响并不显著，在气候变化背景下这一现象尤为突出。分布式空间模型能够为河流管理者提供达成既定管理目标所需的绿色基础设施实施范围相关信息，同时也能揭示雨水截留策略存在的部分局限性。诚然，绿色基础设施虽可提升污水管网应对全球变化的韧性，但仍不足以抵消气候变化对河道径流造成的影响。